1. Field of the Invention
The present invention relates to a method for switching optical channels automatically and synchronously and an apparatus for the same, and more particularly to a technique of scanning for optical signals over a plurality of optical channels so as to automatically and synchronously switch connection among optical terminals and optical channels.
2. Description of Related Art
At the present, wired transmission has been widely used as a medium for data transmission and reception over the Internet. The latest communication media, fiber optic, with the advantages of broadband communication at high speed is becoming increasingly popular on the communication market.
Most communication and electronics suppliers and even building constructors are aware of the tremendous business opportunities behind the development of fiber optic related products, and building constructors even reserve certain space for laying fiber optic lines and connection terminals in the blueprint stage. This phenomenon further confirms the importance and future potential of this type of communication medium. However in view of the relatively high costs of fiber optic materials and fiber optic network set-up costs, only big enterprises and communication operators can afford to set up fiber optic network on their trunk lines so as to satisfy the high volume of data communication.
At present, since fiber optic communication networks are already in operation it needs an appropriate level of repair and maintenance to support the new communication medium. Disclosed is the current practice in handling signal transmission bottlenecks among the trunk lines, to be studied in conjunction with the related circuit layout and equipment set up diagrams in FIG. 7.
Normally, there will be a dedicated spare optical channel TX2/RX2 for preventing breakdown in data transmission if the main channel TX1/RX1 is damaged, and the main channel TX1/RX1 and the spare channel TX2/RX2 are equipped with two optical switches (60) (60a) at two ends. When breakdown in data transmission is detected over the main channel TX1/RX1, operators at both ends of the main channel TX1/RX1 will be notified immediately by phone and asked to switch over the optical switch (60) (60a) to the spare channel TX2/RX2 for resuming the data communication. Usually this is a time-consuming handling procedure that has to be executed manually.
Besides the handling procedure mentioned above, it is feasible to use a control system to control the two optical switches (60)(60a) via a communication line (71). When the master channel TX1/RX1 breaks down, and the control system (70) has acknowledged the breakdown, control signals will be sent over the communication line (71) to both optical switches (60)(60a) causing them to switch over to the spare channel TX2/RX2 simultaneously. Although control of the optical switches (60)(60a) by the control system (71) is capable of overcoming the problem of manual operation, the following disadvantages still remain:
1. An extra controller system needs to be further provided.
2. An extra communication line needs to be set up, and furthermore, it is difficult to set up the communication line, since the distance between the optical switches is usually over 100 km, no matter whether cable, wireless or microwave means are used.
From the handling procedures described above, it is difficult for manual-operated switches to attain high efficiency in the process of channel switching, and it is necessary to dispatch personnel to perform the switchover, which involves extra labor costs and time-consuming. The automated line switchover set up between the main channel and the spare one is not without weakness either, since an additional communication line and a controller system involves considerable investment. Therefore, whether it is a manual handling procedure or an automated line switchover, there are some disadvantages that need to be overcome.
Therefore, the present invention provides a method and an apparatus for switching optical channels automatically and synchronously to mitigate and/or obviate the aforementioned problems.